1) Studies on adoptive transfer of EAE in Strain 13 guinea pigs have yielded significant information on the cellular mechanisms which play a role in that experimental disease. Bacterial lipopolysaccharide (LPS) has been found to activate an essential pathway in the enhancement phenomenon which also depends upon exposure of the cells to specific antigen in culture. In the original studies LPS was unknowingly added to the cultures madium as a contaminant in the fetal calf serum used to supplement the medium. (BP-sensitized cells, cultured with BP, are required but not sufficient for enhanced transfer of EAE). 2) Further studies on enhanced transfer of EAE ln Lewis (Le) rats have developed some important information regarding differences among several mammalian basic proteins in their ability to induce in vitro proliferation and support enhanced transfer of EAE with BP-sensitized spleen cells. Results were correlated with known amino acid differences in the sequences of the encephalitogenic site in the different mammalian BPs. 3) Attempts to demonstrate EAE suppressor cells in Le rats protected against EAE induction have continued to be negative.